Polymerization catalyst, production and use

ABSTRACT

Ethylene and alpha-olefins are homopolymerized or copolymerized with another olefin monomer in the presence of a catalyst system comprising an organo metal cocatalyst and a titanium-containing catalyst component, said titanium-containing catalyst component being obtained by reacting together a porous particulate material, an organic magnesium compound, an oxygen containing compound, a halogen, interhalogen compound or halosilane and titanium tetrachloride.

BACKGROUND OF THE INVENTION

This invention relates to a novel solid catalyst component to beemployed with a cocatalyst for use in the polymerization of olefins topolyolefins such as polyethylene, polypropylene and the like, orcopolymers such as ethylene copolymers with other alpha-olefins anddiolefins, which catalyst component shows unusually high activity andexcellent hydrogen response for the control of polymer molecular weight.The polymer product obtained evidences an important balance of polymerproperties, for example, the catalyst system obtains a polymer with anarrow molecular weight distribution and an improvement in polymerproduct machine direction tear strength and transverse direction tearstrength. As a result, the blown film produced from polymer productmanifests an overall higher strength.

The catalyst component comprises a solid reaction product obtained bycontacting a solid, particulate, porous support material such as, forexample, silica, alumina, magnesium or mixtures thereof for examplesilica-alumina in stages with an organometallic composition treated withan alcohol, a transition metal compound, and a halogen containingcompound, halogen or interhalogen. The novel catalyst component, whichwhen used with an aluminum alkyl cocatalyst, provides the novel catalystsystem of this invention which can be usefully employed for thepolymerization of olefins.

The catalyst system can be employed in slurry, single-phase melt,solution and gas-phase polymerization processes and is particularlyeffective for the production of linear polyethylenes such ashigh-density polyethylene and linear low density polyethylene.

Recently, interest has arisen in the use of magnesium-titanium complexcatalyst components for the polymerization of olefins. For example,European Patent Application No. 27733, published Apr. 29, 1981 disclosesa catalyst component obtained by reducing a transition metal compoundwith an excess of organomagnesium compound in the presence of a supportsuch as silica and thereafter deactivating the excess organomagnesiumcompound with certain deactivators including hydrogen chloride.

U.S. Pat. No. 4,136,058 discloses a catalyst component comprising anorganomagnesium compound and a transition metal halide compound, whichcatalyst component is thereafter deactivated with a deactivating agentsuch as hydrogen chloride. This patent does not teach the use of supportmaterial such as silica but otherwise the disclosure is similar to theabove-discussed European patent application.

U.S. Pat. No. 4,250,288 discloses a catalyst which is the reactionproduct of a transition metal compound, an organomagnesium component andan active non-metallic halide such as HCl and organic halides containinga labile halogen. The catalyst reaction product also contains somealuminum alkyls.

Catalyst components comprising the reaction product of an aluminumalkyl - magnesium alkyl complex plus titanium halide are disclosed inU.S. Pat. Nos. 4,004,071 and 4,276,191.

U.S. Pat. No. 4,173,547 and U.S. Pat. No. 4,263,171, respectivelydisclose a catalyst component comprising silica, an aluminum-typetitanium tetrachloride and dibutyl magnesium and a catalyst componentcomprising a magnesium alkyl - aluminum alkyl complex plus titaniumhalide on a silica support.

The use of chlorine gas in polymerization processes are taught in U.S.Pat. No. 4,267,292 wherein it is disclosed that chlorine gas is to beadded to the polymerization reactor after polymerization has beeninitiated in the presence of a Ziegler catalyst. U.S. Pat. No. 4,248,735teaches subjecting a silica support to a treatment with bromine oriodine and thereafter incorporating a chromium compound onto thesupport. U.S. Pat. No. 3,513,150 discloses the treatment of gammaalumina plus titanium tetrachloride with a gaseous chlorinating agentand employing said treated material in combination with a cocatalyst forthe polymerization of ethylene.

European patent application No. 32,308 discloses polymerizing ethylenein the presence of a catalyst system comprising an organic metalcompound and a titanium-containing material which is obtained byreacting together an inert particulate material, an organic magnesiumcompound, a titanium compound and a halogen containing compound such asSiCl₄, PCl₃, BCl₃, Cl₂ and the like.

Each of U.S. Pat. Nos. 4,402,861, 4,378,304, 4,388,220, 4,301,029 and4,385,161 disclose supported catalyst systems comprising an oxidesupport such as silica, an organomagnesium compound, a transition metalcompound and one or more catalyst component modifiers. These patents donot disclose the advantages taught in this invention.

The catalyst systems comprising magnesium alkyls and titanium compounds,although useful for the polymerization of olefins such as ethylene andother 1-olefins, do not show excellent responsiveness to hydrogen duringthe polymerization reaction for the control of molecular weight, do notreadily incorporate comonomers such as butene-1 for the production ofethylene copolymers, do not show an extremely high catalytic activity.Furthermore, with such catalysts one obtains polymer product whose filmproperties are unbalanced under anisotropic conditions.

In U.S. Pat. No. 4,451,574 issued May 29, 1984, a catalyst systemobtained by treating an inert particulate support, such as silica, withan organometallic compound, a titanium halide and a halogen gas isdisclosed. Although the catalyst obtains very high activity, there is aneed for improving the film properties of polymer product obtained bypolymerizing olefins in the presence of the catalyst and to improve thebulk density of polymer product.

In accordance with this invention catalyst combinations have been foundwhich have extremely high catalytic activities, good comonomerincorporation and excellent hydrogen responsiveness for the control ofmolecular weight and obtain polymer product with greatly improved filmproperties. The resins exhibit excellent melt strength with a surprisingdecrease in power consumption hence an increase in extrusion rates, aswell as excellent MD tear strength in excess of 80 g/mil and dart impactstrength in excess of 70 g/mil with a 1.0 dg/min and 0.918 g/cc densityfilm.

The new catalyst systems which produce polymers having a narrow MWD andcatalyst component of this invention are obtained by contacting anorganometallic comp ound, an alcohol, aldehyde, ketone, siloxane ormixtures thereof, a transition metal compound and a halide containingcompound, halogen or interhalogen compound in the presence of an oxidesupport. The catalyst system employing the transition metal containingcatalyst component is advantageously employed in a gas-phase ethylenepolymerization process since there is a significant decrease in reactorfouling as generally compared with catalytic prior art ethylenegas-phase polymerization processes thereby resulting in less frequentreactor shut downs for cleaning.

SUMMARY OF THE INVENTION

In accordance with the objectives of this invention there is provided atransition metal containing catalyst component for the polymerization ofalpha-olefins comprising a solid reaction product obtained by treatingan inert solid support material in an inert solvent sequentially with(A) an organometallic compound of a Group IIa, IIb or IIIa metal of thePeriodic Table wherein all the metal valencies are satisfied with ahydrocarbon or substituted hydrocarbon group, (B) an oxygen containingcompound selected from ketones, aldehydes, alcohols, siloxanes ormixtures thereof, (C) optionally one or more halogen containingcompounds selected from chlorosilanes and/or Cl₂, Br₂ or interhalogens(D) at least one transition metal compound of a Group IVb, Vb, VIb, VIIor VIII metal of the Periodic Table, (E) optionally Cl₂, Br₂ or aninterhalogen with the proviso that if a chlorosilane is not employed instep (C), then a Cl₂ Br₂ or interhalogen is employed in at least one ofsteps (C) or (E) and with the further proviso that the inert solidsupport material can alternatively be treated with (i) the (A)organometallic compound and the (B) oxygen containing compoundsimultaneously, (ii) the reaction product of the (A) organometalliccompound and (B) oxygen containing compound or (iii) the (B) oxygencontaining compound followed by treating with the (A) organometalliccompound.

The solid transition metal containing catalyst component when employedin combination with a cocatalyst such as an alkyl aluminum cocatalystprovides a catalyst system which demonstrates a number of uniqueproperties that are of great importance in the olefin polymerizationtechnology such as, for example, extremely high catalytic activity, theability to control the molecular weight during the polymerizationreaction as a result of the improved responsiveness to hydrogen,increased polymer yield, and reduced reactor fouling. The polymerproduct obtained from the polymerization of olefins and particularlyethylene manifests improved melt strength and tear strength.

In a preferred embodiment of the invention the (A) organometalliccompound is a dihydrocarbyl magnesium compound represented by R¹ MgR²wherein R¹ and R² which can be the same or different are selected fromalkyl groups, aryl groups, cycloalkyl groups, aralkyl groups, alkadienylgroups or alkenyl groups having from 1 to 20 carbon atoms, the (B)oxygen containing compounds are selected from alcohols and ketonesrepresented by the formula R³ OH and R⁴ COR⁵ wherein R³ and each of R⁴and R⁵ which may be the same or different can be an alkyl group, arylgroup, cycloalkyl group, aralkyl group, alkadienyl group or alkenylgroup having from 1 to 20 carbon atoms, the (D) transition metalcompound is preferably a transition metal compound or combination oftransition metal compounds represented by the formulas TrX'_(4-q)(OR⁶)_(q), TrX'_(4-q) R_(q) ⁷, VO(OR⁶)₃ and VOX'₃ wherein Tr is atransition metal of Groups IVb, Vb, VIb, VIIb and VIII and preferablytitanium, vanadium or zirconium, R⁶ is an alkyl group, aryl group,aralkyl group, substituted aralkyl group having from 1 to 20 carbonatoms and 1,3-cyclopentadienyls, X' is halogen and q is zero or a numberless than or equal to 4, and R⁷ is an alkyl group, aryl group or aralkylgroup having from 1-20 carbon atoms or a 1,3-cyclopentadienyl. In aparticularly preferred embodiment of the invention the (A)organometallic compound and the (B) oxygen containing compound arereacted together prior to contact with the inert support.

All references to the Periodic Table are to the Periodic Table of theElements printed on page B-3 of the 56th Edition of Handbook ofChemistry and Physics, CRC Press (1975).

Although, in accordance with this invention, the order of addition ofingredients in forming the transition metal containing catalystcomponent can vary the catalyst component is preferably prepared byfirst reacting the (A) organometallic compound with the (B) oxygencontaining compound and contacting the reaction product with the inertsolid support material which is preferably a Group IIa, IIIa, IVa or IVbmetal oxide, or a finely divided polyolefin or other suitable supportmaterial and thereafter subjecting the system to treatment with thehalogen containing compound followed by the transition metal compound.In an alternative preferred embodiment the halogen treatment can beperformed after the transition metal compound treatment.

In a second embodiment of this invention there is provided a catalystsystem comprising the transition metal containing solid catalystcomponent and an organoaluminum cocatalyst for the polymerization ofalpha-olefins using the catalyst of this invention under conditionscharacteristic of Ziegler polymerization.

In view of the high activity of the catalyst system prepared inaccordance with this invention as compared with conventional Zieglercatalysts, it is generally not necessary to deash polymer product sincepolymer product will generally contain lower amounts of catalystresidues than polymer product produced in the presence of conventionalcatalyst.

The catalyst systems can be employed in a gas-phase process, singlephase melt process, solvent process or slurry process. The catalystsystem is usefully employed in the polymerization of ethylene and otheralpha-olefins, particularly alpha-olefins having from 3 to 8 carbonatoms and copolymerization of these with other 1-olefins or diolefinshaving from 2 to 20 carbon atoms, such as propylene, butene, pentene andhexene, butadiene, 1,4-pentadiene and the like so as to form copolymersof low and medium densities. The supported catalyst system isparticularly useful for the polymerization of ethylene andcopolymerization of ethylene with other alpha-olefins in gas-phaseprocesses.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Briefly, the catalyst components of the present invention comprises thesolid reaction product of (A) an organometallic composition, (B) anoxygen containing compound, (D) at least one transition metal compoundand (C) and/or (E) halide containing halogen or interhalogen compound inthe presence of an oxide support material. According to thepolymerization process of this invention, ethylene, at least onealpha-olefin having 3 or more carbon atoms or ethylene and other olefinsor diolefins having terminal unsaturation are contacted with thecatalyst under polymerizing conditions to form a commercially usefulpolymeric product. Typically, the support can be any of the solidparticulate porous supports such as talc, zirconia, thoria, magnesia,and titania. Preferably the support material is a Group IIa, IIIa, IVaand IVb metal oxide or mixtures thereof in finely divided form.

Suitable inorganic oxide materials which are desirably employed inaccordance with this invention include silica, alumina, andsilica-alumina and mixtures thereof. Other inorganic oxides that may beemployed either alone or in combination with the silica, alumina orsilica-alumina are magnesia, titania, zirconia, and the like. Othersuitable support materials, however, can be employed. For example,finely divided polyolefins such as finely divided polyethylene.

The metal oxides generally contain acidic surface hydroxyl groups whichwill react with the organometallic composition or transition metalcompound first added to the reaction solvent. Prior to use, theinorganic oxide support is dehydrated, i.e., subjected to a thermaltreatment in order to remove water and reduce the concentration of thesurface hydroxyl groups. The treatment is carried out in vacuum or whilepurging with a dry inert gas such as nitrogen at a temperature of about100° to about 1000° C., and preferably from about 300° C. to about 800°C. Pressure considerations are not critical. The duration of the thermaltreatment can be from about 1 to about 24 hours. However, shorter orlonger times can be employed provided equilibrium is established withthe surface hydroxyl groups.

Chemical dehydration as an alternative method of dehydration of themetal oxides support material can advantageously be employed. Chemicaldehydration converts all water and hydroxyl groups on the oxide surfaceto inert species. Useful chemical agents are for example, SiCl₄,chlorosilanes, silylamines and the like. Chemical dehydration isaccomplished by slurrying the inorganic particulate material, such as,for example, silica in an inert low boiling hydrocarbon, such as, forexample, heptane. During the dehydration reaction, the silica should bemaintained in a moisture and oxygen-free atmosphere. To the silicaslurry is then added a low boiling inert hydrocarbon solution of thedehydrating agents, such as, for example, dichlorodimethylsilane. Thesolution is added slowly to the slurry. The temperature ranges duringthe dehydration reaction can be from about 25° C. to about 120° C.Higher and lower temperatures can be employed. Preferably, thetemperature will be about 50° to 70° C. The chemical dehydrationreaction should be allowed to proceed until all the moisture is removedfrom the particulate support material, as indicated by cessation of gasevolution. Normally, the chemical dehydration reaction will be allowedto proceed from about 30 minutes to about 16 hours, preferably 1 to 5hours. Upon completion of the chemical dehydration, the solidparticulate material is filtered under a nitrogen atmosphere and washedone or more times with a dry, oxygen-free inert hydrocarbon solvent. Thewash solvents, as well as the diluents employed to form the slurry andthe solution of chemical dehydrating agent, can be any suitable inerthydrocarbon. Illustrative of such hydrocarbons are heptane, hexane,toluene, isopentane and the like.

The preferred (A) organometallic compounds employed in this inventionare the inert hydrocarbon soluble organomagnesium compounds representedby the formula R¹ MgR² wherein each of R¹ and R² which may be the sameor different are alkyl groups, aryl groups, cycloalkyl groups, aralkylgroups, alkadienyl groups or alkenyl groups. The hydrocarbon groups R¹or R² can contain between 1 and 20 carbon atoms and preferably from 1 toabout 10 carbon atoms. Illustrative but non-limiting examples ofmagnesium compounds which may be suitably employed in accordance withthe invention are diethylmagnesium, dipropylmagnesium,di-isopropylmagnesium, di-n-butylmagnesium, di-isobutylmagnesium,diamylmagnesium, dioctylmagnesium, di-n-hexylmagnesium,didecylmagnesium, and didodecylmagnesium, dicycloalkylmagnesium, such asdicyclohexylmagnesium; diarylmagnesiums such as dibenzylmagnesium,ditiolylmagnesium and dixylylmagnesium.

Preferably the organomagnesium compounds will have from 1 to 6 carbonatoms and most preferably R¹ and R² are different. Illustrative examplesare ethylpropylmagnesium, ethyl-n-butylmagnesium, amylhexylmagnesium,n-butyl-s-butylmagnesium, n-butyl-n-octylmagnesium and the like.Mixtures of hydrocarbyl magnesium compounds may be suitably employedsuch as for example dibutyl magnesium and ethyl-n-butyl magnesium.

The magnesium hydrocarbyl compounds are as generally obtained fromcommercial sources as mixtures of the magnesium hydrocarbon compoundswith a minor amount of aluminum hydrocarbyl compound. The minor amountof aluminum hydrocarbyl is present in order to facilitate solubilizationof the organomagnesium compound in hydrocarbon solvent. The hydrocarbonsolvent usefully employed for the organomagnesium can be any of the wellknown hydrocarbon liquids, for example hexane, heptane, octane, decane,dodecane, or mixtures thereof, as well as aromatic hydrocarbons such asbenzene, toluene, xylenes, etc.

The organomagnesium complex with a minor amount of aluminum alkyl can berepresented by the formula (R¹ MgR²)_(p) (R₃ ⁸ Al)_(s) wherein R¹ and R²are defined as above with R⁸ having the same definition as R¹ and R² andp is greater than 0. The ratio of s/s+p is from 0 to 1, preferably from0 to about 0.7 and most desirably from about 0 to 0.1.

Illustrative examples of the magnesium aluminum complexes are [(n--C₄H₉)(C₂ H₅)Mg][(C₂ H₅)₃ Al]₀.02, [(nC₄ H₉)₂ Mg][(C₂ H₅)₃ Al]₀.013, [(nC₄H₉)₂ Mg][(C₂ H₅)₃ Al]₂.0 and [(nC₆ H₁₃)₂ Mg][(C₂ H₅)₃ Al]₀.01. Asuitable magnesium aluminum complex is Magala® BEM manufactured by TexasAlkyls, Inc.

The hydrocarbon soluble organometallic compositions are known materialsand can be prepared by conventional methods. One such method involves,for example, the addition of an appropriate aluminum alkyl to a soliddialkyl magnesium in the presence of an inert hydrocarbon solvent. Theorganomagnesium-organoaluminum complexes are, for example, described inU.S. Pat. Nos. 3,737,393 and 4,004,071 which are incorporated herein byreference. However, any other suitable method for preparation oforganometallic compounds can be suitably employed.

The oxygen containing compounds which may be usefully employed inaccordance with this invention are alcohols, aldehydes, siloxanes andketones. Preferably the oxygen containing compounds are selected fromalcohols and ketones represented by the formulas R³ OH and R⁴ COR⁵wherein R³ and each or R⁴ and R⁵ which may be the same or different canbe alkyl groups, aryl groups, cycloalkyl groups, aralkyl groups,alkadienyl groups, or alkenyl groups having from 2 to 20 carbon atoms.Preferably the R groups will have from 2 to 10 carbon atoms. Mostpreferably the R groups are alkyl groups and will have from 2 to 6carbon atoms. Illustrative examples of alcohols which may be usefullyemployed in accordance with this invention are methanol, ethanol,isopropanol, 1-butanol, t-butanol, 2-methyl-1-pentanol, 1-pentanol,1-dodecacanol, cyclobutanol, cyclohexanol, benzyl alcohol, and the like;diols, such as 1,6-hexanediol, and the like with the proviso that thediol can be contacted with the magnesium compound subsequent to themagnesium compound treatment of the support material. Most preferablythe alcohol will contain from 1 to 4 carbon atoms. The most preferredalcohol is 1-butanol.

The ketones will preferably have from 3 to 11 carbon atoms. Illustrativeketones are methyl ketone, ethyl ketone, propyl ketone, n-butyl ketoneand the like. Acetone is the ketone of choice.

Illustrative of the aldehydes which may be usefully employed in thepreparation of the organomagnesium compound include formaldehyde,acetaldehyde, propionaldehyde, butanal, pentanal, hexanal, heptanal,octanal, 2-methylpropanal, 3-methylbutanal, acrolein, crotonaldehyde,benzaldehyde, phenylacetaldehyde, o-tolualdehyde, m-tolualdehyde, andp-tolualdehyde.

Illustrative of the siloxanes which may be usefully employed in thepreparation of the organomagnesium compound includehexamethyldisiloxane, octamethyltrisiloxane,octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,sym-dihydrotetramethyldisiloxane, pentamethyltrihydrotrisiloxane,methylhydrocyclotetrasiloxane, both linear and branchedpolydimethylsiloxanes, polymethylhydrosiloxanes,polyethylhydrosiloxanes, polymethylethylsiloxanes,polymethyloctylsiloxanes, and polyphenylhydrosiloxanes.

The transition metal compounds which can be usefully employed in thepreparation of the transition metal containing catalyst component ofthis invention are well known in the art. The transition metals whichcan be employed in accordance with this invention may be represented bythe formulas TrX'_(4-q) (OR⁶)_(q), TrX'_(4-q) R_(q) ⁷, VOX'₃ andVO(OR⁶)₃. Tr is a Group IVb, Vb, VIb, VIIb, and VIII metal, preferablyGroup IVb and Vb metals and preferably titanium, vanadium or zirconium,q is 0 or a number equal to or less than 4, X' is halogen and R⁶ is ahydrocarbyl or substituted hydrocarbyl group, for example, alkyl, arylor cycloalkyl having from 1 to 20 carbon atoms and R⁷ is an alkyl group,aryl group, aralkyl group, substituted aralkyl group,1,3-cyclopentadienyls and the like. The aryl, aralkyls and substitutedaralkyls contain from 1 to 20 carbon atoms preferably 1 to 10 carbonatoms. Mixtures of the transition metal compounds can be employed ifdesired.

Illustrative examples of the transition metal compounds include: TiCl₄,TiBr₄, Ti(OCH₃)₃ Cl, Ti(OC₂ H₅)Cl₃, Ti(OC₄ H₉)₃ Cl, Ti(OC₃ H₇)₂ Cl₂,Ti(OC₆ H₁₃)₂ Cl₂, Ti(OC₈ H₁₇)₂ Br₂, and Ti(OC₁₂ H₂₅)Cl₃.

As indicated above, mixtures of the transition metal compounds may beusefully employed, no restriction being imposed on the number oftransition metal compounds which may be reacted with the organometalliccomposition. Any halogenide and alkoxide transition metal compound ormixtures thereof can be usefully employed. The titanium tetrahalides areespecially preferred with titanium tetrachloride being most preferred.

The optional treatment (C) with a halogen containing compound isaccomplished with a halosilane, halogen, interhalogen, or mixturethereof. The halosilanes most usefully employed in accordance with thisinvention are represented by the formula R_(b) ⁹ SiX".sub.(4-b) whereinb is less than 4 and greater than 0, R⁹ is hydrogen or a hydrocarbylgroup, and preferably an alkyl group containing from 1 to 10 carbonatoms, most preferably 1 to 6 carbon atoms or an aryl, alkaryl oraralkyl group containing from 6 to up to 18 carbon atoms, and X" is ahalogen selected from chlorine, bromine and iodine. Most preferred ischlorine.

Illustrative of the silanes which may usefully be employed in accordancewith this invention are trichlorosilane, chlorotrimethylsilane,dichlorodimethylsilane, dichlorodiethylsilane, dichlorodibutylsilane,trichlorobutylsilane, trichloromethylsilane, tribromosilane,bromotrimethylsilane and the like. Preferably R⁹ is hydrogen or an alkylgroup. The most preferred halosilane is trichlorosilane.

The halogens which can be suitably employed in accordance with thisinvention are Cl₂, Br₂, I₂ and mixtures thereof. Illustrativeinterhalogen compounds are ClF, ClF₃, BrF, BrF₃, BrF₅, ICl, ICl₃ andIBr. The preferred halogens are Cl₂ and Br₂. Most preferably Cl₂ isemployed. The preferred interhalogens contain Br or Cl. The halogensemployed in optional step (E) are Cl₂, Br₂ and the interhalogens listedsupra.

In accordance with this invention, either step (C) or step (E) or bothmust be employed in the preparation of the catalyst. Preferably Cl₂ willbe employed as the compound of choice for the halogenation treatment.The treatment in step (C) or step (E) or both can be usefully performedin accordance with this invention, however, the at least step (C)halogen treatment is preferred.

The treatment of the support material as mentioned above is conducted inan inert solvent. The inert solvents can also be usefully employed todissolve the individual ingredients prior to the treatment step.Preferred solvents include mineral oils and the various hydrocarbonswhich are liquid at reaction temperatures and in which the individualingredients are soluble. Illustrative examples of useful solventsinclude the alkanes such as pentane, iso-pentane, hexane, heptane,octane and nonane; cycloalkanes such as cyclopentane, cyclohexane; andaromatics such as benzene, toluene, ethylbenzene and diethylbenzene. Theamount of solvent to be employed is not critical. Nevertheless, theamount should be employed so as to provide adequate heat transfer awayfrom the catalyst components during reaction and to permit good mixing.

The organometallic component employed in step (A) either as theorganometallic compound or its reaction product with an oxygencontaining compound is preferably added to the inert solvent in the formof a solution. Preferred solvents for the organometallic compositionsare the alkanes such as hexane, heptane, octane and the like. However,the same solvent as employed for the inert particulate support materialcan be employed for dissolving the organometallic composition. Theconcentration of the organometallic composition in the solvent is notcritical and is limited only by handling needs.

The amount of materials usefully employed can vary over a wide range.The concentration of magnesium deposited on the essentially dry, inertsupport can be in the range from about 0.1 to about 2.5 millimoles/g ofsupport, however, greater or lesser amounts can be usefully employed.Preferably, the organomagnesium compound concentration is in the rangeof 0.5 to 2.0 mmoles/g of support and more preferably in the range of1.0 to 1.8 mmoles/g of support. The magnesium to oxygen-containingcompound mole ratio can be from about 0.01 to about 2.0 . Preferably,the ratio is in the range of 0.5 to 1.5, and more preferably within therange of 0.8 to 1.2. The upper limit on this range is dependent on achoice of oxygen-containing compound and the mode of addition. When theoxygen-containing compound is not pre-mixed with the magnesium compound,that is, when it is added to the support before the magnesium compoundor after the magnesium compound, the ratio may range from 0.01 to 2.0.When pre-mixed with the organomagnesium compound, the hydrocarbyl groupson the oxygen-containing compound must be sufficiently large to insuresolubility of the reaction product. Otherwise, the ratio ofoxygen-containing compound to organomagnesium compound ranges from 0.01to 1.0, most preferably 0.8 to 1.0.

The amount of halosilane to be optionally employed should be such as toprovide a halogen to magnesium mole ratio of about 0.5 to about 3.0. Thehalogen or interhalogen treatment in either step (C) or (E) or both issuch as to provide an excess of the halogen or interhalogen. Generally,the halogen employed, such as for example Cl₂, is employed in the formof a gas.

The halogen treatment of the catalyst can be accomplished by exposingthe catalyst in either dry or slurry form to gaseous chlorine at 1.0 to10 atmospheres total pressure for about 10 minutes to 4 hours attemperatures ranging from about 0° to 100° C. A mixture of Cl₂ and aninert gas such as argon or nitrogen can also be employed. The molarconcentration of chlorine in the inert gas can range from 1 mole % to100 mole %.

The transition metal compound is added to the inert support at aconcentration of about 0.01 to about 1.5 millimoles Ti/g of driedsupport, preferably in the range of about 0.05 to about 1.0 millimolesTi/g of dried support and especially in the range of about 0.1 to 0.8millimoles Ti/g of dried support.

Generally, the individual reaction steps can be conducted astemperatures in the range of about -50° C. to about 150° C. Preferredtemperature ranges are from about -30° C. to about 60° C. with -10° C.to about 50° C. being most preferred. The reaction time for theindividual treatment steps can range from about 5 minutes to about 24hours. Preferably the reaction time will be from about 1/2 hour to about8 hours. During the reaction constant agitation is desirable.

In the preparation of the transition metal-containing solid catalystcomponent, washing after the completion of any step may be effected.However, it is generally found that the material advantages of thecatalyst system are diminished by washing until the completion of step(E).

The catalyst component prepared in accordance with this invention areusefully employed with cocatalysts well known in the art of the Zieglercatalysis for polymerization of olefins. Typically, the cocatalystswhich are used together with the transition metal containing catalystcomponent are organometallic compounds of Group Ia, IIa, IIIa metalssuch as aluminum alkyls, aluminum alkyl hydrides, lithium aluminumalkyls, zinc alkyls, magnesium alkyls and the like. The cocatalystsdesirably used are the organoaluminum compounds. The preferredalkylaluminum compounds are represented by the formula AlR"'_(n)X"_(3-n) wherein R"' is hydrogen, hydrocarbyl or substituted hydrocarbylgroup and X" is halogen or alkoxide as are well known in the art.Preferably R"' is an alkyl group having from 2 to 10 carbon atoms.Illustrative examples of the cocatalyst material are ethyl aluminumdichloride, ethyl aluminum sesquichloride, diethyl aluminum chloride,aluminum triethyl, aluminum tributyl, diisobutyl aluminum hydride,diethyl aluminum ethoxide and the like. Aluminum trialkyl compounds aremost preferred with triisobutylaluminum being highly desirable.

The catalyst system comprising the aluminum alkyl cocatalyst and thetransition metal containing catalyst component is usefully employed forthe polymerization of ethylene, other alpha-olefins having from 3 to 20carbon atoms, such as for example, propylene, butene-1, pentene-1,hexene-1, 4 methylpentene-1, and the like and ethylene copolymers withother alpha-olefins or diolefins such as 1,4-pentadiene, 1,5-hexadiene,butadiene, 2-methyl-1,3-butadiene and the like. The polymerizablemonomer of preference is ethylene. The catalyst may be usefully employedto produce polyethylene or copolymers of ethylene by copolymerizing withother alpha-olefins or diolefins, particularly propylene, butene-1,pentene-1, hexene-1, and octene-1. The olefins can be polymerized in thepresence of the catalysts of this invention by any suitable process suchas, for example, suspension, solution and gas-phase processes.

The polymerization reaction employing catalytic amounts of theabove-described catalyst can be carried out under conditions well knownin the art of Ziegler polymerization, for example, in an inert diluentat a temperature in the range of 50° C. to 120° C. and a pressure of 1to 40 atmospheres, in the gas phase at a temperature range of 70° C. to100° C. at about 1 atmosphere to 50 atmospheres and upward. Illustrativegas-phase processes are disclosed in U.S. Pat. Nos. 4,302,565, and4,302,566, which references are incorporated by reference. As indicatedabove, an advantageous property of the catalyst system of this inventionis the reduced amount of gas-phase reactor fouling. The catalyst systemcan also be used to polymerize olefins at single phase conditions, i.e.,150° C. to 320° C. and 1,000 to 3,000 atmospheres. At these conditions,the catalyst lifetime is short but the activity sufficiently high thatremoval of catalyst residues from the polymer is unnecessary. However,it is preferred that the polymerizations be performed at pressuresranging from 1 to 50 atmospheres, preferably 5 to 25 atmospheres.

In the processes according to this invention it has been discovered thatthe catalyst system is highly responsive to hydrogen for the control ofmolecular weight. Other well known molecular weight controlling agentsand modifying agents, however, may be usefully employed.

The polyolefins prepared in accordance with this invention can beextruded, mechanically melted, cast or molded as desired. They can beused for plates, sheets, films and a variety of other objects.

While the invention is described in connection with the specificexamples below, it is understood that these are only for illustrativepurposes. Many alternatives, modifications and variations will beapparent to those skilled in the art in light of the below examples andsuch alternatives, modifications and variations fall within the generalscope of the claims.

Preparation of Silica

In the Examples following the silica was prepared by one of thefollowing methods:

(a) Silica support was prepared by placing Davison Chemical CompanyG-952 silica gel in a vertical column and fluidizing with an upward flowof nitrogen. The column was heated slowly to 800° C. and held at thattemperature for 12 hours after which the silica was allowed to cool toambient temperature.

(b) Davison Chemical Company G-952 silica gel was placed in a clean, dry500 ml Schlenk flask equipped with a Friedrichs condenser containing astirring bar. The flask was flushed with nitrogen for 1 hour and the 10g sample of the silica gel was slurried in 100 ml of dry, oxygen-freeheptane and heated to 70° C. while stirring. To the slurry was added 70mmoles of dimethyldichlorosilane over a 1 hour period with continuousstirring. Upon completion of the silane addition the stirring wascontinued for 3 hours. The sample was cooled to room temperature,filtered and washed 3 times with 50 ml aliquots of heptane. The samplewas dried under vacuum and stored under nitrogen.

The melt index (MI) and melt index ratio were measured in accordancewith ASTM test D1238. The resin density was determined by densitygradient column according to ASTM test D1505. The bulk density wasdetermined by allowing approximately 120 cc of resin to fall from thebottom of a polyethylene funnel across a gap of 1 inch into a tared 100cc plastic cylinder (2.6 cm in diameter by 19.0 cm high). The funnelbottom was covered with a piece of cardboard until the funnel was filledwith the sample. The entire sample was then allowed to fall into thecylinder. Without agitating the sample, excess resin was scraped away sothat the container was completely filled without excess. The weight ofresin in the 100 cc cylinder was determined. This measurement wasrepeated three times and the average value reported.

EXAMPLE 1

A 2.0 g portion of the chemically dried silica was slurried in 20 ml ofdry, oxygen-free hexane in a 50 ml centrifuge tube containing a stirringbar. The silica was maintained at 20° C. while stirring in hexane. 5.20ml of a 1.15 mmole/ml solution of a 1:1 molar ratio ofbutylethylmagnesium (BEM) and butanol in hexane was added slowly bysyringe and stirred for 3 hours at 20° C. The solid portion wasrecovered by decantation, washed 2 times with ml aliquots of hexane. Thewashed solid was reslurried in 20 ml of hexane, heated to 50° C. and 8.0ml of a 0.5 mmole/ml of TiClW1₄ and hexane was slowly added. The slurrywas stirred for 3 hours at 50° C. The slurry was cooled to roomtemperature, the solid recovered by decantation and washed 2 times with30 ml aliquots of hexane. The recovered solid was reslurried in 20 ml ofhexane and chlorinated by pressurizing the centrifuge tube toapproximately 7.5 psig with chlorine gas and stirring for 30 minutes atroom temperature. The tube was vented, flushed out with nitrogen, thesample decanted, washed 3 times with 30 ml aliquots of hexane and driedat room temperature under vacuum in a dry box.

Polymerization

0.075 g of the recovered dry catalyst was injected into a 2 literreactor maintained at 85° and containing 875 ml of hexane, 30 psig ofH₂, 20 ml of butene-1 and pressured to a total pressure of 150 psig withethylene. Polymerization was continued for 40 minutes.

The results of the polymerization are summarized in Table 1.

EXAMPLE 2

Example 2 was performed identically as in Example 1 with the exceptionthat the silica was prepared in accordance with (a) above. The resultsof the polymerization are summarized in Table 1.

EXAMPLE 3

Example 3 was performed identically as in Example 1 with the exceptionthat 7.0 ml of a 0.5 mmole per ml trichlorosilane solution in hexane wasadded after the BEM addition step. The trichlorosilane addition wasperformed at 20° C. with stirring and continued for 2 hours after theaddition of the stirrant. The sample was cooled to room temperature,decanted and washed 2 times with 30 ml aliquots of hexane. The recoveredsolid was reslurried in 20 ml of hexane before the TiCl₄ addition. Theresults of the polymerization are summarized in Table 1.

EXAMPLE 4

Example 4 was performed identically as in Example 3 with the exceptionthat the thermally treated (a) silica was employed in place of thechemically treated silica. The results of the polymerization aresummarized in Table 1.

EXAMPLE 5

Example 5 was performed identically as in Example 1 with the exceptionthat the final Cl₂ addition step was eliminated and no washing wasperformed between the individual steps. The results of thepolymerization are summarized in Table 1.

EXAMPLE 6

Example 6 was performed identically as in Example 1 with the exceptionthat BEM was added to the support material without butanol. The resultsof the polymerization are summarized in Table 1.

EXAMPLE 7

Example 7 was performed identically as in Example 2 with the exceptionthat butanol was eliminated from the catalyst preparation. The resultsof the polymerization are summarized in Table 1.

The data in Table 1 indicates that the use of butanol in combinationwith BEM significantly decreases the molecular weight distribution ofthe polymer. The use of a chemical dehydrating agent for the silicadecreases MWD further. The intermediate chlorinating agent improved thecatalyst activity by at least a factor of 2 and the final chlorinetreatment employed in combination with the chemical dehydrated silicaobtains polymer product having higher bulk density than catalystprepared on thermally dehydrated supports.

                  TABLE I                                                         ______________________________________                                                          MI              Bulk Density                                Example   Asp.sup.(1)                                                                           (dg/min)   MIR  (g/cc)                                      ______________________________________                                        1         30.3    2.76       25.2 0.37                                        2         27.2    2.46       28.4 0.32                                        3         70.4    2.70       25.7 0.35                                        4         84.1    6.80       29.3 0.26                                        5         34.3    --         --   0.26                                        6         11.9    1.67       44.3 0.31                                        7         12.0    0.54       52.7 0.30                                        ______________________________________                                         .sup.(1) Asp is the catalyst specific activity which has units of kg of       polymer produced per gram of Ti per hour per atmosphere of ethylene.     

What is claimed is:
 1. A transition metal containing catalyst componentcomprising the solid reaction produce obtained by treating an inertsolid support material in an inert solvent sequentially with (A) anorganometallic compound of a Group IIa, IIb or IIIa metal wherein allthe metal valencies are satisfied with a hydrocarbon group, (B) anoxygen containing compound selected from ketones, aldehydes, alcohols,siloxanes or mixtures thereof, (C) optionally one of more halogencontaining compounds selected from chlorosilanes represented by theformula R_(b) ⁹ SiX".sub.(4-b) wherein 0O<b<4, X" is chlorine, bromineor iodine and R⁹ is a hydrocarbyl group having from 1-18 carbon atomsand/or Cl₂, Br₂ or interhalogens, (D) at least one transition metalcompound of a Group IVb, Vb, VIb or VIII metal, (E) optionally Cl₂, Br₂or an interhalogen with the proviso that if a chlorosilane is notemployed in step (C), then a Cl₂, Br₂ or interhalogen is employed in atleast one of steps (C) or (E), and with the further proviso that theinert solid support material can also be treated with (i) the (A)organometallic compound and the (B) oxygen containing compoundsimultaneously, (ii) the reaction product of the (A) organometalliccompound and (B) oxygen containing compound or (iii) the (B) oxygencontaining compound followed by treating with the (A) organometalliccompound, the mole ratio of the organometallic compound to the oxygencontaining compound being in the range of about 0.5 to 1.5.
 2. Thetransition metal containing catalyst component of claim 1 wherein the(A) organometallic compound is a dihydrocarbon magnesium compoundrepresented by R¹ MgR² wherein R¹ and R² which can be the same ordifferent are selected from alkyl groups, aryl groups, cycloalkylgroups, aralkyl groups, alkadienyl groups or alkenyl groups, the oxygencontaining compounds are selected from alcohols and ketones representedby the formula R³ OH and R⁴ COR⁵ wherein R³ and each of R⁴ and R⁵ whichmay be the same or different can be an alkyl group, aryl group,cycloalkyl group, aralkyl group, alkadienyl group or alkenyl group. 3.The transition metal containing catalyst component of claim 2 whereinthe inert solid support material is one of silica, aluminum, magnesiumor mixtures thereof.
 4. The transition metal containing catalystcomponent of claim 2 wherein R¹, R², R³, R⁴, and R⁵ are alkyl groupshaving from 1 to 10 carbon atoms.
 5. The transition metal containingcatalyst component of claim 2 wherein R¹ and R² are different.
 6. Thetransition metal containing catalyst component of claim 5 wherein R¹, R²and R³ are alkyl groups having from 1 to 6 carbon atoms.
 7. Thetransition metal containing catalyst component of claim 6 wherein R¹ isbutyl.
 8. The transition metal containing catalyst component of claim 7wherein R² is ethyl.
 9. The transition metal containing catalystcomponent of claim 6 wherein R¹, R², R³, R⁴ and R⁵ have 1 to 4 carbonatoms.
 10. The transition metal containing catalyst component of claim 9wherein the oxygen containing component is an alcohol.
 11. Thetransition metal containing catalyst component of claim 10 wherein R³ isbutyl.
 12. The transition metal containing catalyst component of claim 2wherein the transition metal compound or mixtures thereof is representedby the formula TrX'_(4-q) (OR⁶)_(q), TrX'_(4-q) R_(q) ⁷, VOX'₃ orVO(OR⁶)₃ wherein Tr is a transition metal, R⁶ is a hydrocarbyl grouphaving from 1 to 20 carbon atoms, R⁷ is an alkyl group, aryl group oraralkyl group having from 1 to 20 carbon atoms or a1,3-cyclopentadienyl, X' is halogen and q is 0 or a number equal to orless than
 4. 13. The transition metal containing catalyst component ofclaim 12 wherein Tr is titanium, vanadium or zirconium.
 14. Thetransition metal containing catalyst component of claim 13 wherein thetransition metal compound is TiCl₄.
 15. The transition metal containingcatalyst component of claim 2 wherein chlorosilane is employed in stepC.
 16. The transition metal containing catalyst component of claim 15wherein chlorine is employed in step E.
 17. The transition metalcontaining catalyst component of claim 2 wherein chlorine is employed instep C.
 18. The transition metal containing catalyst component of claim16 wherein step C is omitted.
 19. The transition metal containingcatalyst component of claim 2 wherein the organomagnesium compound andthe oxygen containing compound are reacted together prior to contactwith the inert support material.
 20. The transition metal containingcatalyst component of claim 19 wherein the oxygen containing compound isan alkyl alcohol having from 1 to 4 carbon atoms and the magnesiumcontaining compound is ethyl-n-butylmagnesium.
 21. A catalyst system forthe polymerization of copolymerization of ethylene and alpha-olefinshaving from 3 to 12 carbon atoms comprising (a) an organo aluminumcompound of the formula AlR"_(n) X"_(3-n) wherein R" is hydrogen or ahydrocarbon group having from 1 to 20 carbon atoms, X is halogen and nis a number from 1 to 3, and (b) a transition metal containing catalystcomponent comprising the solid reaction product obtained by treating aninert solid support material in an inert solvent sequentially with (A)an organometallic compound of a Group IIa, IIb or IIIa metal wherein allthe metal valencies are satisfied with a hydrocarbyl group, (B) anoxygen containing compound selected from ketones, aldehydes, alcohols,siloxanes or mixtures thereof, (C) optionally one or more halogencontaining compounds selected from chlorosilanes represented by theformula R_(b) ⁹ SiX".sub.(4-b) wherein 0O<b<4, X" is chlorine, bromineor iodine and R⁹ is a hydrocarbyl group having from 1-18 carbon atomsand/or Cl₂ , Br₂ or interhalogens, (D) at least one transition metalcompound of a Group IVb, Vb, VIb or VIII metal, (E) optionally Cl₂, Br₂or an interhalogen with the proviso that if a chlorosilane is notemployed in step (C), then a Cl₂, Br₂ or interhalogen is employed in atleast one of steps (C) or (E), and with the further proviso that theinert solid support material can also be treated with (i) the (A)organometallic compound and the (B) oxygen containing compoundsimultaneously, (ii) the reaction product of the (A) organometalliccompound and (B) oxygen containing compound or (iii) the (B) oxygencontaining compound followed by treating with the (A) organometalliccompound, the mole ratio of the organometallic compound to the oxygencontaining compound being in the range of about 0.5 to 1.5.
 22. Thecatalyst system of claim 21 wherein the (A) organometallic compound is adihydrocarbon magnesium compound represented by R¹ MgR² wherein R¹ andR² which can be the same or different are selected from alkyl groups,aryl groups, cycloalkyl groups, aralkyl groups, alkadienyl groups oralkenyl groups, the oxygen containing compounds are selected fromalcohols and ketones represented by the formula R³ OH and R⁴ COR⁵wherein R³ and each of R⁴ and R⁵ which may be the same or different canbe an alkyl group, aryl group, cycloalkyl group, aralkyl group,alkadienyl group or alkenyl group.
 23. The catalyst system of claim 22wherein the inert solid support material is one of silica, aluminum,magnesium or mixtures thereof.
 24. The catalyst system of claim 22wherein R¹, R², R³, R⁴, and R⁵ are alkyl groups having from 1 to 10carbon atoms.
 25. The catalyst system of claim 22 wherein R¹ and R² aredifferent.
 26. The catalyst system of claim 25 wherein R¹, R² and R³ arealkyl groups having from 1 to 6 carbon atoms.
 27. The catalyst system ofclaim 26 wherein R¹ is butyl.
 28. The catalyst system of claim 27wherein R² is ethyl.
 29. The catalyst system of claim 26 wherein R¹, R²,R³, R⁴ and R⁵ have 1 to 4 carbon atoms.
 30. The catalyst system of claim29 wherein the oxygen containing component is an alcohol.
 31. Thecatalyst system of claim 30 wherein R³ is butyl.
 32. The catalyst systemof claim 22 wherein the transition metal compound or mixtures thereof isrepresented by the formula TrX'_(4-q) (OR⁶)_(q), TrX'_(4-q) R_(q)⁷,VOX'₃ or VO(OR⁶)₃ wherein Tr is a transition metal, R⁶ is ahydrocarbyl group having from 1 to 20 carbon atoms, R⁷ is an alkylgroup, aryl group or aralkyl group having from 1 to 20 carbon atoms or a1,3-cyclopentadienyl, X' is halogen and q is 0 or a number equal to orless than
 4. 33. The catalyst system of claim 32 wherein Tr is titanium,vanadium or zirconium.
 34. The catalyst system of claim 33 wherein thetransition metal compound is TiCl₄.
 35. The catalyst system of claim 22wherein chlorosilane is employed in step C.
 36. The catalyst system ofclaim 35 wherein chlorine is employed in step E.
 37. The catalyst systemof claim 22 wherein chlorine is employed in step C.
 38. The catalystsystem of claim 36 wherein step C is omitted.
 39. The catalyst system ofclaim 22 wherein the organomagnesium compound and the oxygen containingcompound are reacted together prior to contact with the inert supportmaterial.
 40. The catalyst system of claim 39 wherein the oxygencontaining compound is an alkyl alcohol having from 1 to 4 carbon atomsand the magnesium containing compound is ethyl-n-butylmagnesium.